The nuclide having maximum value of binding energy per nucleon is

The correct answer is Option (3) → \( {}^{56}_{26}\mathrm{Fe} \)

The curve of binding energy per nucleon against mass number rises steeply for light nuclei, has a broad maximum of about 8.8 MeV per nucleon near \( A \approx 56 \) (iron), and then falls slowly for heavier nuclei. The most tightly bound nucleus among the four is therefore the one nearest the top of the curve.

The approximate values are: \( {}^{27}\mathrm{Al} \) about 8.3 MeV, \( {}^{56}\mathrm{Fe} \) about 8.8 MeV, \( {}^{208}\mathrm{Pb} \) about 7.9 MeV and \( {}^{238}\mathrm{U} \) about 7.6 MeV per nucleon. Hence iron has the maximum value among the given nuclides.

NCERT (2026-27):
Nuclear Binding Energy – “… Figure 13.1 is a plot of the binding energy per nucleon E_bn versus the mass number A for a large number of nuclei. … The curve has a maximum of about 8.75 MeV for A = 56 and has a value of 7.6 MeV for A = 238.”